A. Field of the Invention
The field of the present invention relates generally to reciprocating motors which utilize a drive mechanism to provide power to an output shaft or crankshaft. More particularly, the present invention relates to such motors in which the magnetic repelling and attracting forces of permanent magnets are utilized to reciprocate a solenoid assembly. Even more particularly, the present invention relates to such motors in which the change in direction of the solenoid assembly is obtained by switching the polarity of a solenoid to alternatively repel and attract the solenoid assembly away from or toward the permanent magnets.
B. Background
Reciprocating motors have been and continue to be used in virtually every available mode of transportation and for all types of power supply needs throughout the entire world. Generally, reciprocating motors have a piston slidably disposed in a cylinder and utilize a driving force to drive the piston in one or both directions inside the cylinder so as to rotate an output shaft, such as a crankshaft. The most commonly utilized reciprocating motor is an internal combustion engine. The typical internal combustion engine comprises a series of cylinders each having a piston reciprocating inside to drive a crankshaft in order to produce motion or power. Air and fuel are combined in the piston chamber, defined inside the cylinder by the top of the piston, and ignited by a spark from a spark plug to provide an explosive driving force that drives the piston downward. The fuel and air are fed into the piston chamber through an intake valve and, after combustion, exhaust air is forced out through an exhaust valve. To obtain proper performance of the fuel/air igniting sequence, the valve activating mechanism must open and close the intake and exhaust valves at the proper times. Due to relatively high engine operating speeds, this process happens at a very fast rate. Due to their extensive use, the internal combustion engine has been the subject of intensive efforts in the United States and most industrialized countries since the beginning of their utilization to improve the engine's operating characteristics. Despite these efforts, internal combustion engines are well known for relatively inefficient utilization of fuel, such as gasoline and other products made from oil, and being significant contributors to the air pollution problems that exist in most cities and towns. As such, the continued use of internal combustion engines is recognized by many persons as a significant draw on the Earth's limited natural resources and a substantial threat to human health.
Other types of reciprocating devices are also well known. For instance, electromagnetic reciprocating engines utilize electromagnetic force as the driving force to move the piston inside the cylinder and rotate the output shaft. A typical configuration for such engines comprises a plurality of electromagnets disposed around the cylinder that are actuated by electrical currents to provide the electromagnetic force necessary to drive the piston in a reciprocating motion in the cylinder. It is well known that this type of electromagnetic engine must have a somewhat large supply of electrical current to power the electromagnets and typically requires a complex control mechanism to provide the electrical current to the electromagnets in a manner required to operate the engine. For these and other practical reasons, electromagnetic reciprocating engines have generally not become very well accepted.
Another source of power that has been utilized to reciprocate a piston inside a cylinder is the magnetic energy stored in permanent magnets. As is well known, when the same polarity ends of two magnets are placed near each other the repulsion force of the two magnetic fields will repel the magnets and, conversely, when the opposite polarity ends of two magnets are placed near each other the attraction force of the magnetic fields will attract the magnets toward each other, assuming one or both of the magnets are allowed to move. A known advantage of utilizing permanent magnets as the driving force for a reciprocating motor is that the energy available from these magnets is relatively constant and capable of providing a long operating life. In order to use permanent magnets to reciprocally drive a piston inside a cylinder, however, a mechanism must be provided that first utilizes the advantage of dissimilar polarity to attract the piston to the permanent magnet and then utilize the advantage of similar polarity to drive the piston away from the permanent magnet. Naturally, this must be done in a very rapid manner at the proper time. The difficulties with being able to rapidly switch polarity when using permanent magnets, as opposed to electromagnetic force, has heretofore substantially limited the ability to utilize the advantages of permanent magnets as a driving force to reciprocate a piston in a cylinder so as to rotate an output shaft for the purposes of motion or the generation of electricity.
Over the years, various reciprocating devices that utilize permanent magnets as the driving force to reciprocate a piston or other actuating devices, to one extent or another, have been patented. For instance, U.S. Pat. No. 3,676,719 to Pecci discloses a electromagnetic motor having an electromagnetic solenoid, located within a concentric counterbore, having a coil disposed about an inner sleeve and electromagnetic insulating end walls at the ends thereof. A ferrous metal core is slidably received in the inner sleeve and reciprocates in response to the electromagnetic force to rotate a drive shaft. U.S. Pat. No. 3,811,058 to Kiniski discloses a reciprocating device having an open-bottomed cylinder having a piston made out of magnetic material, with a predetermined polarity, slidably disposed in the cylinder chamber. A disc rotatably mounted to the engine block below the cylinder has at least one permanent magnet, of like polarity, on the surface facing the open bottom of the cylinder such that the rotation of the disc periodically aligns the permanent magnet with the piston so the repulsive force therebetween causes the piston to reciprocate in the cylinder chamber. U.S. Pat. No. 3,967,146 to Howard discloses a magnetic motion conversion motor having permanent magnets arranged with like poles facing each other and a magnetic flux field suppressor disposed between the magnets for repeatedly causing a magnetic repelling and attracting action as it is moved into alignment between the like poles of the magnets. The magnets reciprocally drive piston rods connected to crankshafts that are connected to a common drive shaft, as the main output shaft. U.S. Pat. No. 4,317,058 to Blalock discloses an electromagnetic reciprocating engine having a nonferromagnetic cylinder with a permanent magnetic piston reciprocally disposed therein and an electromagnet disposed at the outer end of the cylinder. A switching device, interconnecting the electromagnet to an electrical power source, causes the electromagnet to create an electrical field that reciprocates the piston within the cylinder. U.S. Pat. No. 4,507,579 to Turner discloses a reciprocating piston electric motor having a magnetic piston slidably disposed in a nonmagnetic cylinder that has wire coils wrapped around the ends thereof that are electrically activated to reciprocate the piston inside the cylinder to drive a crankshaft connected to the piston by a piston rod. U.S. Pat. No. 5,457,349 to Gifford discloses a reciprocating electromagnetic engine having fixed magnets mounted in the piston that intermittently attract and repel sequentially energized electromagnets that are radially mounted in the cylinder walls. A computerized control mechanism regulates the timing of the electromagnets to reciprocate the piston and drive a rotatable crankshaft. U.S. Pat. No. 6,552,450 to Harty, et al. discloses a reciprocating engine having a piston, which is reciprocally disposed in a cylinder, that is driven by opposing electromagnets connected with the piston and cylinder. A polarity switching mechanism switches polarity to reciprocate the piston. U.S. Pat. No. 7,557,473 to Butler discloses an electromagnetic reciprocating engine comprising an electromagnet with opposing magnetic poles disposed between permanent magnets mounted on either ends of a moving frame connected to a crankshaft. Magnetic attraction and repulsion forces are used to reciprocate the frame and rotate the crankshaft.
One of the major disadvantages associated with previously disclosed or presently available permanent magnet reciprocating motors is that mechanism for switching polarity to reciprocally drive the piston in the cylinder generally utilizes one or more electromagnets, some of which have a complicated switching mechanism that interconnects a power source with the electromagnets. A significant problem with the use of an electromagnet to reciprocate a piston to or away from a permanent magnet is that the force field of the permanent magnet is strongly attracted to the iron core of the electromagnet. This strong magnetic attraction force makes it very difficult, if not impossible, for the magnetic repelling force to overcome the attraction between the permanent magnet and the iron core, thereby eliminating the repel step (of the attract/repel action) that is necessary to reciprocate the piston in response to the magnetic switching. If the strong magnetic attraction between the permanent magnet and the iron core can be overcome, it requires an excessive amount of energy for the electromagnet. Other devices utilize an electric motor or other prime mover to rotate or pivot a member having the permanent magnets so as to periodically attract or repel magnets on the piston to provide the force necessary for reciprocating the piston. Naturally, the use of an external prime mover substantially reduces the energy efficiency of the magnetically actuated reciprocating motor and, therefore, one of the primary benefits of such motors. Another major disadvantage that is associated with presently available magnetically actuated reciprocating motors is that the switching mechanisms are generally somewhat complicated and subject to malfunction or cessation of operation.
The present inventor is also the inventor of co-pending U.S. patent application Ser. No. 11/356,372 (published as U.S. Publication No. 2006/0131887 on Jun. 22, 2006), which describes a magnetically actuated reciprocating motor utilizing a magnetic switching device having a magnetic fixture with at least two rare earth magnets positioned such that an opposite magnetic polarity of each magnet is directed toward the head of a reciprocating piston magnet having a magnetic polarity that is directed toward the magnetic fixture. The reciprocating motion of the piston rotates an output shaft that operatively connects to and rotatably drives a controlling mechanism that attaches to the magnetic fixture in a manner that switches which magnet, and therefore which magnetic polarity, is directed toward the piston to attract or repel the piston, rotate a crankshaft and accomplish useful work. The present inventor is also the inventor of co-pending U.S. patent application Ser. No. 12/832,928 (hereinafter, the “'928 Application”) that describes a magnetically actuated motor which utilizes an electrically charged solenoid to provide electromagnetic force and reciprocatively move an elongated magnetic actuator having a permanent magnet at each of its ends. The coil of the solenoid is wrapped around a nonferrous spool that is fixedly held in position and the shaft of the actuator linearly moves inside the spool in response to one of the permanent magnets of the magnetic actuator being repelled by the solenoid while the other permanent magnet is being drawn toward the solenoid as a result of the polarity of the electromagnetic force at the ends of the coil being alternated by a switching device connecting the coil with a source of power. Reciprocation of the magnetic actuator drives an output shaft that rotates a work object. The magnetically actuated reciprocating motor of the '928 Application does not utilize an electromagnet and, as a result, eliminates the problems associated with the permanent magnets being attracted to the iron core of the electromagnet.
Despite the foregoing, what is needed is an improved magnetically actuated reciprocating motor that has an improved reverse magnetic switching mechanism for switching magnetic polarities and driving a connecting rod that rotatably drives an output shaft. As with the '928 Application an improved reciprocating motor should not utilize an iron core electromagnet in magnetically cooperation with permanent magnets so as to eliminate the excessive attraction that can occur between the permanent magnets and the iron core electromagnet. The reciprocating motor should not use a prime mover or the like to reciprocate permanent magnets from an attracting position to a repelling position so as to reciprocally drive a piston disposed in a cylinder. The preferred reciprocating motor should be relatively simple to operate, require a limited number of moving components and be relatively inexpensive to manufacture. The preferred reciprocating motor should connect to a crankshaft or other output shaft to produce rotary power and be adaptable to a wide variety of reciprocating motor uses, including vehicle motion and power generation.